Luminaire



P. R. MILROY July 22, 1969 LUMINAIRE 5 Sheets-Sheet 1 Filed Feb. 25,1966 PMpZ 11M? July 22, 1969 M|LROY 3,457,399

LUMINAIRE Filed Feb. 25, 1966 3 Sheets-Sheet 2 MJW July 22, 1969 P. R.MILROY 3,457,399

LUMINAIRE Filed Feb. 25, 1966 3 Sheets-Sheet L,-

States 3,457,399 LUMINAIRE Philip R. Milroy, Hendersonville, N.C.,assignor to genital Electric Company, a corporation of New Filed Feb.25, N66, Ser. No. 530,214 Int. Cl. F215 13/10 U.S. Cl. 240-25 ClaimsABSTRACT OF THE DISCLOSURE The present invention relates to luminaires,and more particularly concerns luminaires having sealed optical systemsprotected from the entry of contaminating materials in the atmosphere.

Luminaires of known type, such as those used for street lighting andother purposes, are subject to the disadvantage that when installed inan industrial or other environment having atmospheres containingimpurities or contaminants of various kinds, the illuminating andoptical systems of the luminaires become dulled or degraded by depositsof the impurities on their surfaces, resulting in a reduced level ofillumination produced thereby. Even when gaskets are used between thejoints of the luminaire parts, the contaminated air passes into and outof the interior of the optical system. Such movement of the air may bedue to the differential pressures which are built up between theinterior and the exterior of the optical system by variation intemperature within the luminaire during the operating and non-operatingcycles. On the other hand, providing a completely hermetic seal forknown types of luminaire optical systems involves practical and economicdifliculties due to the elevated temperatures of modern luminaires, thedifferential pressures which develop therein during operation and otherfactors.

It is an object of the invention to provide lighting devices, especiallyluminaires, having improved protection for their illuminating andoptical components from the effect of impure atmospheres in which theyoperate, and to thereby prolong the effective life of the optical systemand maintain a high illumination level thereof.

It is a particular object of the invention to provide luminaires of theabove type having a sealed optical system and means for purifying theair which passes into the optical system.

It is another object of the invention to provide in luminaires or thelike a sealed, filtered optical system of the above type which iseconomically manufactured, is

easily assembled, and is readily maintained, and which avoids the needfor frequent servicing and cleaning thereof.

Still another object of the invention is to provide a combined filterand sealing system of the above type which is readily adaptable forapplication to a wide variety of illuminating devices.

Other objects and advantages will become apparent from the followingdescription and the appended claims.

With the above objects in view, the present invention in one of itsaspects relates to a luminaire comprising, in combination, a reflectorand a refractor separably secured together and forming a closed opticalsystem, a lamp aratent O 3,457,399 Patented July 22, 1969 ranged withinthe closed optical system, resilient sealing means between the reflectorand refractor forming an airtight seal for the closed optical system,and air-permeable purifying filter means inserted into the closedoptical system for filtering the air passing thereinto by removal ofsolid and gaseous impurities contained therein, the lamp duringoperation heating the air in the closed optical system to an elevatedtemperature, whereby heated air is expelled outwardly through the filterduring operation of the lamp, and cool air is drawn inwardly through thefilter and purified thereby when the lamp is not operating.

The invention will be better understood from the following descriptiontaken in conjunction with the accom' panying drawings, in which:

FIGURE 1 is a view in elevation, partly broken away, of a streetlighting luminaire embodying the present invention;

FIGURE 2 is an enlarged detailed view in cross section of a portion ofthe FIGURE 1 luminaire showing the seal between the luminaire reflectorand refractor of th FIGURE 1 device;

FIGURE 3 is a plan view of the rear portion of the refractor showing therefractor retaining means;

FIGURE 4 is a detailed view in cross section of a portion of the FIGURE1 luminaire showing the sealing and air filter means arranged inaccordance with the invention;

FIGURE 5 is a perspective view of the rear portion of the structureshown in FIGURE 4;

FIGURE 6 is a perspective view of the filter device employed in theFIGURE 1 luminaire;

FIGURE 7 is a perspective view of a different type of luminaire, partlybroken away, which may embody the present invention;

FIGURE 8 is an enlarged fragmentary view, partly in section, of theFIGURE 7 luminaire showing the sealing arrangement for the opticalsystem; and

FIGURE 9 is a detailed view of a rim portion of the FIGURE 7 luminaireshowing the seal arrangement and latch means for the transparentclosure.

Referring now to the drawings, and particularly to FIG- I URE 1, thereis shown a street lighting luminaire comprising an elongated upperhousing 1 adapted to be mounted at its rear end on a pipe support 7 andhaving secured therein at its front portion a concave reflector 2,typically of aluminum, having a specular interior reflecting surfacefacing downwardly towards the bottom opening of housing 1. The housingopening is closed by a bowlshaped light transmitting globe or refractor3 mounted in a ring-shaped retaining frame 4 which is swingablyconnected at its rear end to housing 1 by hinge means 5 which pivots ontransverse support member 25, and is releasably attached at its frontend to housing 1 by latch means 6. The particular hinge connection ofrefractor retaining frame 4 to housing 1 and other structural features(which do not form a part of the present invention) are shown in greaterdetail in co-pending application Ser. No. 533,054, filed Mar. 4, 1966,now Patent 3,353,015 issued Nov. 14, 1967 and assigned to the sameassignee as the present invention.

Reflector 2 is secured to housing 1 by means of screws at its front end,such as screw 2a threadedly engaging a depending boss 1a in housing 1.At its rear end, reflector 2 is releasably mounted by means ofrearwardly projecting tangs 2b (see FIGURES 4 and 5) which are insertedinto slots in transverse support member 25 secured to housing 1, as morefully described and shown in the abovementioned co-pending application.

Upon release of latch 6, refractor ring 4 with refractor 3 retainedtherein may be swung downwardly about hinge 5 to provide access to theinterior of the luminaire housing for re-lamping or other servicingoperations. Upon closing refractor 4 and latching it to housing 1, re-

fractor 3 is brought into tight sealing engagement with reflector 2 asmore fully described below.

As seen in FIGURE 2, refractor 3 is formed with a flange 3a extendingaround its rim and resting upon annular ridge 4b of ring 4 which extendsaround the opening in the latter in which refractor 3 is received. Thefront end of refractor 3 is held in place on ring 4 by a plurality ofinwardly projecting retaining members 9 integral with outer ridge 4:: ofring 4 and engaging portions of flange 3a of refractor 3. Formed on theupper edge of refractor 3 is an annular bead 3b which in the closedposition of refractor retaining ring 4 engages and compresses gasket 7attached to reflector 2.

As seen in FIGURE 3, refractor retaining ring 4 has a refractorretaining clip 8 pivotally secured therto adjacent the rear portion ofrefractor 3. After refractor 3 is inserted into ring 4 with its annularflange 3a resting on supporting ridge 4b, and with the front end portionof flange 3a inserted beneath retaining members 9, clip 8 is turned fromthe open position (shown in broken lines) to the locking position (shownin continuous lines) in which it overlaps flange 3a of refractor 3,thereby retaining the refractor in assembly with ring 4.

Reflector 2 is formed with a peripheral flange 2a (see FIGURE 2) whichoverlies the rim of refractor 3 in the closed position. Gasket 7 whichprovides a seal between reflector 2 and refractor 3 is an annular memberof suitably resilient material resistant to high temperatures, such asethylene-propylene-terpolymer elastomer material or the equivalent. Asseen in cross-section, the gasket has an upper U-shaped portion 7a whichslips snugly over reflector flange 2a around its circumference, and hasintergral therewith a tubular portion 7b which is compressed by bead 3bof refractor 3 in the closed assembly, as seen in FIGURE 2. Preferably,the refractor engaging surface of gasket portion 7b is formed with aseries of spaced integral ribs (not shown) extending continuously aroundits length to provide optimum sealing engagement with refractor 3.

Reflector 2 is formed with an opening at its rear which is closed by acup-shaped housing 10 in which a lampholder or socket 11 is adjustablysecured for holding lamp 12, such as a mercury vapor, sodium vapor, orother type of lamp. The structure providing the adjustable mounting ofsocket 11 within housing 10 is shown and described in detail inco-pending application Ser. No. 530,213, filed Feb. 25, 1966, now Patent3,348,035 issued Oct. 17, 1967, and assigned to the same assignee as thepresent application, and does not constitute a part of the presentinvention. Housing 10 has a flange portion 10a at its front end (seeFIGURE and is secured to reflector 2 around its rear opening by means ofrivets 13 spaced around the flange portion. The surface of flangeportion a facing the reflector wall is formed with an annular recess(see FIGURE 4) surrounding the rim of housing 10, in which resilientgasket 14 is received and compressed between flange 10a and the rearwall of reflector 2. The outermost edge of flange portion 10a is incontact with the rear surface of reflector 2, and the depth of theannular recess in flange portion 10a is so dimensioned with respect tothe thickness of gasket 14 that the gasket is under limited uniformcompression in the riveted assembly of housing 10 to reflector 2, andprovides a tight permanent seal at the joint therebetween.

In acordance with a significant aspect of the invention, a permeable airpurifying filter is arranged in the otherwise air-tight optical systemof the luminaire to permit passage of air into and out of the opticalsystem and to remove dust, dirt, and other contaminants of gaseous orparticulate nature which may be contained in the air and which wouldadversely affect the illuminating level of the optical system, such asby forming dulling films, depositing materials corrosive to ordiscoloring the reflecting surface of reflector 2, or otherwiseinterfering with the function of the refractor, reflector and lamp. Inthe em- 4 bodiment shown in FIGURES 1-5, the air purifying means isconstituted by a filter cartridge 15 (see FIGURE 6) comprising a bondedcylindrical mass 16 of activated charcoal particles contained within atubular holder 17 of resilient materials such as that of the gasketspreviously described, and plugging rear opening 10b in housing 10.Holder 17 is open at opposite ends and is formed at one end on its outersurface with concentric annular lips 17a, 17b defining an annular groovetherebetween in which the edges of housing 10 defining rear opening 10bare snugly received and grasped by lips 17a, 17b in sealing relation.Filter cartridge 15 may thereby be readily attached and removed from therear opening in socket housing 10.

Insulated lead wires 18, 19 (see FIGURES 4 and 5) connected to theterminals of socket 11 pass through a small aperture in housing 10 whichis plugged by a resilient plug or bushing 20 having a pair of holesthrough which lead wires 18, 19 extend. Bushing 20 tightly fits withinand is radially compressed by the edges of aperture of 100 and therebyin turn tightly compresses lead wires 18, 19, thus providing anair-tight bushing.

As a result of the described arrangement, the only means available forair to flow into and out of the interior of the closed illuminating andoptical assembly, which includes reflector 2, refractor 3 and lamp 12,is through the low resistance path provided by the filter mass 16. Allother possible paths for passage of air are of very much higherresistance to low velocity air flow. By virute of such a low resistancepath provided by the filter, there will be no sustained difference inpressure between the inside and outside of the optical assembly. Anypressure differences which may arise by operation of the luminaire orfor other reasons are rapidly equilized.

When the lamp in the luminaire is turned on, the elevated temperaturewhich develops inside the optical assembly may rise as high as C. As aresult, the air therein expands and flows outwardly at a very slow ratethrough filter 16. When the lamp is turned off, the interior of theopictal assembly cools off and air is drawn back into the opticalassembly, also at a Very slow rate. During this period when air entersthe optical assembly, filter 16 acts to remove any organic and inorganiccontaminants in the air, both of gaseous and particulate type. Particleshave above about .1 micron in size will be screened by the activatedcharcoal out of the air as it passes through the filter. contaminates ofgaseous type, such as found in industrial fumes, smog, auto exhaustproducts such as hydrocarbons, and the like, will be removed byadsorption by the filter particles. The relative dimensions of filtermass 16 should preferably be such that its diameter is large enough toaflord low resistance to the volume of air passing through the filter,while its thickness is large enough to provide adequate mechanicalstrength for handling without risk of breakage. In a typical case, thediameter would be about 1% and the thickness about In a commerciallyavailable activated charcoal filter product satisfactory for thepurposes of the invention, the charcoal particles have a size withinU.S. sieve sizes 20 to 50 and are bonded by a thermally resistant bindermaterial.

Initial tests made using street lighting luminaires equipped withactivated charcoal filters in accordance with the invention compared tostandard unfiltered luminaire units indicate that even in a moderatelycontaminated atmosphere over a period of 11 months of the loss of lighttransmission through the refractor in the filtered units is only about10% as compared to about 30% loss for the standard unfiltered units.

While filters composed of bonded activated charcoal particles areparticularly suitable for the purposes of the invention, other types offilter materials which purify air by a combination of screening outsolid particles and removal of gaseous contaminants by absorption mayalternatively be employed, as for example, activated alumina,

clays, magnesia, gels and silicates. However, activated charcoal ispreferred because it specifically adsorbs hydrocarbon vapors inpreference to water.

FIGURE 7 shows a different type of luminaire in which the presentinvention may be embodied. This luminaire is adapted for indoor use, asfor example, in factory areas where the atmosphere may adversely affectthe optical and illuminating system of the luminaire. As seen in FIG-URES 7 and 8, the luminaire comprises a bell-shaped reflector 30 whichhas an interior specular reflecting surface and is secured to anintermediate support housing 31, which in turn is supported from ballasthousing 32 and separated therefrom for thermal insulating purposes byspacers 51. Lamp 33, such as a mercury vapor or other gas dischargelamp, is removably held in socket 34 secured to the top of housing 31,and extend down into the interior of reflector 30'. Ballast housing 32,which contains electrical ballast components (not shown) for operatingdischarge lamp 33, is releasably secured to upper support member 40 bymeans of hinge 41 and latch 42, support member 40 being normally securedto a pipe conduit for supporting the luminaire unit therefrom and havingan opening in the top for passage of electrical conductors therethrough(not shown).

Housing 31 is formed with a series of circumferentially spaced openings31a which are closed by an annular transparent window 35 such as glasswhich is mounted within housing 31 just inside openings 31a andencircling the upper portion of lamp 33. Light from lamp 33 is thustransmitted upwardly out of the luminaire through window openings 31a(so-called up light), as well as downwardly through the bottom openingof reflector 30. The bottom opening is closed by a glass pane 36 havinga peripheral molding strip 37 which is hingedly connected to thereflector 30 by hinge 38. As seen in FIGURE 9, latch 39 which serves toreleasably secure window pane 36 to reflector 30 in closed positioncomprises plate members 39a, 39b secured respectively to window pane 36and reflector 30, and screw 39c which interconnects members 39a, 3% bythreaded engagement with member 39a.

In accordance with the present invention, this luminaire is providedwith a sealed optical system in which air from the atmosphere ispermitted to pass only through a purifying filter. To this end, theannular joint between the upper part of glass window 35 and windowhousing 31 is sealed by gasket 43 which is of tubular, air core type.The seal between the bottom edge of glass window 35 and the surface ofreflector 30 on which it rests is provided by an annular flat gasket 44.The upper end of support housing 31 adjacent the bottom of ballasthousing 32 is sealed by means of a resilient plug or bushing 45 havingtwo aperture for passage of insulated lead wires 46, 47 connected tosocket 34, in which apertures the latter wires are tightly gripped bythe radial compression on plug 45 due to its tight fit in the apertureat the top of housing 31.

Bottom window 36 is sealed to reflector 30 by means of gasket 48 (seeFIGURE 9) which comprises, in cross section, a U-shaped portion 48ainterposed between edge molding 37 and glass pane 36, and a tubularportion 48b interposed between the upper surface of edge molding 37 andthe bottom surface of reflector flange 30a. In the closed position ofwindow 36, tubular gasket portion 48b is compressed as shown in FIGURE 9to provide an airtight seal around the bottom opening of reflector 30.Each of gaskets 43, 44, 48 and plug 45 are preferably made of aresilient thermally-resistant material such as theethylene-propylene-terpolymer elastomer material mentioned previously,or equivalent materials.

Filter cartridge 15 (see FIGURE 7) identical to filter device 15 shownin FIGURES 4-6 is inserted in an aperture in reflector 30 and issecurely but removably held therein in the same manner as filter device15 is mounted in housing of the FIGURE 1 luminaire. The interior of theoptical system of the FIGURE 7 luminaire is thus sealed except for thepassage provided through filter which serves to purify air entering theoptical system substantially as described in connection with the FIG-URE 1 luminaire.

It will be understood that filter 15 may be inserted in the opticalsystem of luminaires at locations other than as shown and describedherein, as dictated by the particular structure and needs of theluminaire unit in which it is used.

There is thus provided by the invention a luminaire which breathes onlypurified air, from which both solid and gaseous contaminating materialshave been removed. As a result, the deleterious effects of corrosiveimpurities and dulling films on the luminaire optical system are reducedto a remarkable degree, and the initially high level of illuminationproduced by the luminaire is maintained over a long period of time, evenin heavily contaminated atmospheres in industrial, smog and similarenvironments. There is also avoided thereby the frequent cleaning of theoptical system such as heretofore found necessary with ordinaryluminaires installed in such environments. At the same time, thefilter-sealed arrangement of the invention is readily and economicallymanufactured, is applicable to a wide variety of luminaire and otherlighting devices, and makes use of filter devices which are easilyremovable and replaceable, and can be used interchangeably in differentoptical systems.

While the present invention has been described with reference toparticular embodiments thereof, it will be understood that numerousmodifications may be made by those skilled in the art without actuallydeparting from the scope of the invention. Therefore, the appendedclaims are intended to cover all such equivalent variations as comewithin the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In a luminaire, a housing, a reflector and light transmitting closuremeans secured together in sealed relation forming a closed opticalenclosure, means for mounting a lamp in said enclosure, andair-permeable, gas-adsorbent filter means arranged on said closedoptical enclosure communicating with the interior thereof for filteringthe air passing thereinto by removal of solid and gaseous impuritiescontained in the air, said filter means constituting the sole passagewayfor heated air expelled outwardly from said enclosure and for air drawninto the enclosure when the latter is cooled, said housing closing anopening in said reflector and said filter means communicating with theinterior of said enclosure through an aperture in said housing.

2. In a luminaire, a housing, a reflector and light transmitting closuremeans secured together in sealed relation forming a closed opticalenclosure, means for mounting a lamp in said enclosure, andair-permeable, gas adsorbent filter means arranged on said closedoptical enclosure communicating with the interior thereof for filteringthe air passing thereinto by removal of solid and gaseous impuritiescontained in the air, said filter means constituting the sole passagewayfor heated air expelled outwardly from said enclosure and for air drawninto the enclosure when the latter is cooled, said filter meanscommunicating with the interior of said enclosure through an aperture insaid reflector.

3. A device as defined in claim 2, said reflector having a bottomopening and an upper opening, said housing having an annular portionsurrounding said upper refiector opening and having window openingstherein, said light transmitting closure means comprising a firsttransparent closure closing said bottom reflector opening and a secondtransparent closure closing said housing window openings fortransmitting light upwardly from said lamp means to the exterior of theluminaire.

4. A device as defined in claim 3, including resilient gasket meanssealing said reflector, said light transmitting closure means and saidannular housing portion to each other in air-tight relation.

57 In aluminaire, a reflector and a transparent closure thereforseparably secured together and forming a closed optical system, sealingmeans between said reflector and said transparent closure forming anair-tight seal for said closed optitcal system, and air-permeablepurifying filter means inserted into said closed optical system forfiltering the air passing therethrough .by removal of solid and gaseousimpurities contained therein, lamp means arranged in said closed opticalsystem, said lamp means during operation heating the air in said closedoptical system to elevated temperature, whereby heated air is expelledoutwardly through said filter means during operation of said lamp means,and cool air is drawn inwardly through said filter means and purifiedthereby when said lamp means is not operating, said reflector beingconcave and having an annular rim, said transparent closure beingbowl-shaped and having a peripheral edge portion in mating relation withsaid reflector rim, said sealing means comprising a resilientthermally-resistant gasket secured to one of said reflector and saidtransparent closure and interposed in sealing relation therebetween,said reflcetor having an opening in a wall thereof, said opening benigclosed by a housing, lamp socket means mounted in said housing forholding said lamp means, said housing being sealed to said reflectorwall and having an aperture therein, said filter means being inserted inand closing said aperture, said housing having a second aperture,resilient plug means closing said second aperture, and elongatedconducting means connected to said lamp socket means and passingoutwardly through said resilient plug means in air-tight sealingrelation therewith.

6. In a luminaire, a reflector and a transparent closure thereforseparably secured together and forming a closed optical system, sealingmeans between said reflector and said transparent closure forming anair-tight seal for said closed optical system, and air-permeablepurifying filter means inserted into said closed optical system forfiltering the air passing therethrough by removal of solid and gaseousimpurities contained therein, lamp means arranged in said closed opticalsystem, said lamp means during operation heating the air in said closedoptical system to elevated temperature, whereby heated air is expelledoutwardly through said filter means during operation of said lamp means,and cool air is drawn inwardly through said filter means and purifiedthereby when said lamp means is not operating, said filter meanscommunicating with the interior of said optical system through anaperture in said reflector, said reflector having a bottom openingclosed by said transparent closure and having an upper opening, windowhousing means enclosing said upper opening and being transparent in atleast a portion thereof for transmitting light upwardly from said lampmeans to the exterior of the luminaire, and lampholder means secured tosaid window housing means for holding said lamp means extending intosaid optical system.

7. A device as defined in claim 6, said window housing means comprisingan annular member secured to the top of said reflector extending aroundsaid upper open ing thereof and having window openings spacedtherearound, an annular transparent window arranged concentricallywithin said annular member closing the window opening thereof, andresilient gasket means sealing said reflector, said annular housingmember and said annular transparent window to each other in air-tightrelation.

8. A device as defined in claim 7, said annular housing member having atop wall, an upper housing overlying and secured to said top wall andadapted to contain electrical components for operating said lamp means,said top wall having an aperture leading to the interior of the adjacentupper housing, resilient plug means closing said aperture, and elongatedconductor means connected to said lampholder means and passing into saidupper housing through said resilient plug means in airtight sealingrelation therewith.

9. A device as defined in claim 7, said sealing means between saidreflector and said transparent closure comprising an annular gasket ofthermally-resistant resilient material, said transparent closure beinghingedly connected at one side to said reflector and having latch meanson its opposite side attachable to said reflector for releasably holdingsaid transparent closure in closed, airtight sealing relation with saidreflector.

10. In a luminaire, a reflector and a transparent closure thereforseparably secured together and forming a closed optical system, sealingmeans between said reflector and said transparent closure forming anairtight seal for said closed optical system, and air-permeablepurifying filter means inserted into said closed optical system forfiltering the air passing therethrough by removal of solid and gaseousimpurities contained therein, said reflector having a wall portionassociated therewith forming a part of the enclosure for the opticalsystem, said wall portion defining an aperture, said filter meanscomprising air-filtering material held in a tubular holder, said tubularholder being formed on its outer surface with juxtaposed resilient lipportions extending around said holder and defining an annular groovetherebetween, said holder fitting within said aperture with its annulargroove receiving the edges defining said aperture, so that saidresilient lip portions respectively engage opposite sides of said wallportion for tightly but removably mounting said filter holder in saidwall portion.

References Cited UNITED STATES PATENTS 3,350,860 11/1967 Grassel et al.-387 3,376,695 4/1968 Muckley 55387 1,900,330 3/1933 Chartrand 240253,089,025 5/1963 Brisco 240-25 3,315,072 4/1967 Harling 24025 FOREIGNPATENTS 575,976 3/ 1946 Great Britain.

JOHN M. HORAN, Primary Examiner RICHARD M. SHEER, Assistant Examiner US.Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,457,399 July 22, 1969 Philip R. Milroy It is certified that error appearsin the above identified patent and that said Letters Patent are herebycorrected as shown below:

Column 2, line 72 "refractor 4" should read refractor ring 4 Column 3line 33, "intergral" should read integral Column 4, line 30, viruteshould read virtue line 34, "equilized should read equalized line 40,"opictal should read optical line 45 cancel have"; line 47,"Contaminates" should read Contaminants line 66, "months of the loss"should read months the loss line 74, "absorption should read adsorptionColumn 7 line 5, optitca1" should read optical line 21, "reflcetor"should read reflector line 22, "benig should read being Signed andsealed this 14th day of April 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer

